On 5/7/19 7:03 AM, Colin King wrote:
From: Colin Ian King <colin.king@xxxxxxxxxxxxx>
Currently if the allocation of roots or tmp_ulist fails the error handling
does not free up the allocation of path causing a memory leak. Fix this and
other similar leaks by moving the call of btrfs_free_path from label out
to label out_free_ulist.
Kudos to David Sterba for spotting the issue in my original fix and
providing the correct way to fix the leak.
Addresses-Coverity: ("Resource leak")
Fixes: 5911c8fe05c5 ("btrfs: fiemap: preallocate ulists for btrfs_check_shared")
Signed-off-by: Colin Ian King <colin.king@xxxxxxxxxxxxx>
---
V2: move the btrfs_free_path to the out_free_ulist label as suggested by
David Sterba as the correct fix.
---
fs/btrfs/extent_io.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index 1eb671c16ff1..31127f6d2971 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -4766,11 +4766,11 @@ int extent_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
ret = emit_last_fiemap_cache(fieinfo, &cache);
free_extent_map(em);
out:
- btrfs_free_path(path);
unlock_extent_cached(&BTRFS_I(inode)->io_tree, start, start + len - 1,
&cached_state);
out_free_ulist:
+ btrfs_free_path(path);
ulist_free(roots);
ulist_free(tmp_ulist);
return ret;
Now this causes double free.
$ git diff
diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index 6b154bce5687..61ebdccca04b 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -4611,7 +4611,6 @@ int extent_fiemap(struct inode *inode, struct
fiemap_extent_info *fieinfo,
ret = btrfs_lookup_file_extent(NULL, root, path,
btrfs_ino(BTRFS_I(inode)), -1, 0);
if (ret < 0) {
- btrfs_free_path(path);
goto out_free_ulist;
} else {
WARN_ON(!ret);
